1. Field of the Invention
The present invention relates to a radio communication device for data transmission and reception, and more specifically, to a technology related to arrangement of circuits composing the radio communication device.
2. Description of Related Art
FIG. 6 is a schematic block diagram of a conventional radio communication device 100. The radio communication device 100 includes: an MAC/BB circuit 101 so configured as to include a data controller (MAC(Media access controller)) which controls a data signal to be transmitted or received and a base band processor (BB) which modulates and demodulates a data signal; an RF circuit (RF converter circuit) 102 that superposes a carrier wave signal of a predetermined frequency band on a modulated signal; and a high frequency circuit 103 that wirelessly transmits and receives a signal via an antenna 105. The MAC/BB circuit 101 performs digital signal processing, while the RF circuit 102 and the high frequency circuit 103 perform analog signal processing.
Normally, in circuits up to the base band processor (BB) which perform digital signal processing, a digital-analog converter circuit 104 is included which converts a digital signal from the base band processor into an analog signal in the RF circuit 102.
Part of the circuits shown in FIG. 6 is formed on one or more integrated circuits, which are mounted on a board. FIG. 7 is a plane view of a component mounting surface of the board on which the radio communication device 100 is mounted. Mounted on this component mounting surface of the board are: an MAC/BB integrated circuit 201 loading the MAC/BB circuit 101 and the digital-analog converter circuit 104 and an RF integrated circuit 202 loading the RF circuit 102; and also the high frequency circuit 103 in such a manner as to surround the RF integrated circuit 202 from all round.
Further, on the component mounting surface of the board, a power supply circuit, and a balun, a filter, and the like in the high frequency circuit 103, all not shown are mounted to thereby form the radio communication device 100.
JP-A-H8-204344 discloses a technology of loading an analog circuit and a digital circuit on the same multilayer wiring board in a mixed manner.
In recent years, more and more radio communication devices have been loaded in compact, portable devices. Thus, there has been demand for a compact radio communication device which is completed with a single module and which can be used without making a designer of the device to consider a high frequency circuit that requires advanced knowledge.
However, to load a radio communication device in a smaller device, when the conventional radio communication device as shown in FIGS. 6 and 7 is mounted on a smaller board, in particular, a high frequency analog circuit part, such as the high frequency circuit 103, and a digital signal processor, such as the MAC/BB circuit 101 are located close to each other. Thus, noise from the digital signal processor is superposed on a weak signal in the high frequency analog circuit part, thus resulting in a problem that a required SIN ratio cannot be ensured especially upon reception of the weak signal.